The researchers also found that mothers took more risks – like increased smoking – during pregnancies with second and third children.

The researchers say these findings might shed light on the “birth order effect”, wherein first-born children tend to make more money or get higher education than their younger siblings.

“Broad shifts in parental behavior are a plausible explanation for the observed birth order differences in education and labor market outcomes,” said study author Ana Nuevo-Chiquero of the University of Edinburgh School of Economics.

First-borns, try not to lord this information over your younger siblings too much; if you must, be sure to explain it very slowly.